The invention proceeds from a method for controlling the transmission of data between electronic components, preferably in a motor vehicle, which either supply information or process it, and which are linearly connected to each other and to a controlling component by a data bus.
Methods for controlling the transmission of data between electronic components in a motor vehicle are already known, i.e., methods which help solve the problem of finding space for motor vehicle components which provide information and entertainment by increasing their functionality and complexity in spite of the high level of their integration. This approach leads to networked systems and decentralized components. It is necessary not only to control and monitor information but also to transmit audio and video data as well as possibly the data stored on a CD-ROM (called "data" or "useful data" in the following). A modular concept, which allows the data to be transmitted over coaxial cables or fiber-optic waveguides, usually made of plastic, is required for the transmission of these data. For cost reasons, standard communications protocols are used for these transmissions.
A networking of components in motor vehicles in the form of a star topology is known. In this design, several data sources are connected to a data sink. The number of these sources cannot be exceeded by the limited number of free inputs. In addition, a large amount of space is required, and the large number of plug contacts which the data sink must have is also disadvantageous.
Optical ring structures are also known, in which both data and control/monitoring information are transmitted over the transmission medium. Each component, whether data source or data sink, has an optoelectronic converter at its input and an electro-optic converter at its output. A protocol processor makes it possible for the data to be read in and out. In a ring structure, the data stream must be clocked. The disadvantage of a ring topology and of the transmission of all the data over the same medium is the fact that a break at any point puts the entire network out of service. Components in a ring structure which have no data burden of their own beyond information for control and monitoring, e.g., remote controls, have an oversized interface.